diff --git a/python/pyspark/ml/util.py b/python/pyspark/ml/util.py
index c65b3d14be1d..02016f172aeb 100644
--- a/python/pyspark/ml/util.py
+++ b/python/pyspark/ml/util.py
@@ -17,6 +17,7 @@
 
 import sys
 import uuid
+import warnings
 
 if sys.version > '3':
     basestring = str